6.4. A fourth-order polynomial equation is given by x21x3+147x² - 379x+252 = 0 (a) Use Newton-Raphson method and hand calculations to find one of the roots of the polynomial equation. Start with the initial estimate of x(0) = 0 and continue until |Ax()|< 0.001. (b) Write a MATLAB program to find the roots of the above polynomial by Newton-Raphson method. The program should prompt the user to input the initial estimate. Run using the initial estimates of 0, 3, 6, 10. (c) Check your answers using the MATLAB function r = roots(A), where A is a row vector containing the polynomial coefficients in descending powers.